Colorectal carcinoma is a leading cause of morbidity and mortality across the globe. Gastric carcinoma also is a leading concern worldwide. Colonoscopy is the most accurate screening tool for colorectal cancer, and an esophagogastroduodenoscopy is the preferred method for gastric screening. The means by which a diagnosis is made during endoscopy is in question, however. Many techniques of mucosal sampling have been utilized since Hemmeter in 1889 described an abrasive instrument for diagnosing gastric carcinoma. For example, pinch, snare, brush, suction, salvage and fine needle aspiration (FNA) are established sampling techniques for gastrointestinal endoscopy. Lavage cytology is now considered obsolete, but was the technique that cultivated major advances in gastrointestinal cytology. Brush, suction, salvage, and FNA deliver samples appropriate for cyto-analysis and their interpretation rest upon cytology data gleaned for over 100 years. Their practical use, however, is limited because of the time and effort required for completion. Histology samples delivered by pinch and snare techniques, although the more commonly performed because of their rapid results are flawed techniques with lower diagnostic yields than brush, suction and salvage techniques.
Needs exist for a novel means used during endoscopy that dissects tissue into a cellular suspension capable of undergoing analytical cytology.
Fluid jet tubes having operative openings and cell traps for cell cluster, tissue and debris harvesting and collecting are used in diagnostics and therapeutics. Used with an endoscope the fluid jets draw-in, stabilize and hold in vivo target specimens at a distal end. While the catheter grips the tissue by suction, blasts of high pressure saline solution strip from the tissue and suspend clusters of cells which are ready for analysis. The clusters of cells are entrained in the saline solution and are recovered in a cell collection trap at the proximal end. Traps are removed and replaced or rotated out of and into alignment with a trap connector to accommodate new target specimens.
A foot switch controls fluid flow and intensity and frequency of the fluid jet blasts of the saline solution. The fluid jet catheter paired with a fiber optic system in an endoscope allows viewing of the area immediately surrounding the distal end of the catheter.
In diagnostics the tubes and traps are used with flexible and rigid endoscopes. In the therapeutics the tubes and trap are used with rigid endoscopes and in free standing applications to collect cell cluster, tissue and debris samples from arterial thrombectomy, external biopsy, wound debriedment, surgical incisions and surgical excisions.
In one embodiment the present invention uses a flexible endoscope which stabilizes and holds in vivo target specimens at a proximal end. While the endoscope grips the tissue by suction, blasts of high pressure saline solution strip the tissue samples and break the tissue into suspended cells which are ready for analysis.
A fluid-jet catheter of the invention unites the advantageous qualities of conventional techniques into one swift technique allowing for results while consuming fewer resources.
This invention provides a flexible fluid-jet catheter capable of dissecting tissue into a cellular suspension for undergoing analytical cytology. Analytical cytology is a practical and effective approach to medical diagnosis.
The fluid-jet catheter of the present invention uses high velocity saline jets to create a Bernoulli effect for entrapment, dissection and retrieval of tissue cells, providing a novel approach for the diagnosis and treatment of pathology through the flexible endoscope. It fosters new initiatives in tumor diagnosis and management of lesions found by flexible endoscopy.
In other embodiments of the invention cell traps are provided on return lines of abraiding and cutting fluid jets used for arterial thrombectomy, external and internal biopsies, wound debriedment and surgical incisions and excisions to collect cell clusters for further analyzing without further preparation.
High pressure fluid-jets have been successfully used in other medical devices. They have been used to create incisions during surgery, and to clean trauma wounds. The fluid-jet""s application to flexible endoscopy, and specifically for the diagnosis and management of flexible endoscopic pathology has yet to be determined, however.
The fluid-jet dissects tissue into a cellular suspension capable of undergoing analytical cytology. Because of this, diagnostic rates are improved, and, unlike more commonly performed techniques, samples may be analyzed in-vitro with highly specific and sophisticated adjunctive techniques. A greater number of endoscopic lesions are capable of being diagnosed in cellular suspensions rather than permanently fixed in formalin. Eventually, such a rapid system for tissue sampling may stimulate improved techniques for point-of-care, on-site diagnosis. It may also stimulate new treatment modalities for endoscopic pathology in less invasive and more effective ways. It provides a novel means for less invasive treatment of conditions such as Polyposis coli and Barrett""s esophagus.
The fluid-jet of the present invention is capable of being adjusted to various pulsation frequencies, pressures, patterns, fluid compositions, spray patterns and flow rates. In addition, the fluid-jet may be of any size. The fluid-jet provides means for retrieval of cell clusters from freshly dissected tissue. The retrieved tissue is immersed in a cytopreservative for transport of tissue freshly dissected by a fluid-jet.
Ideally, a limited range of fluid-jet settings would allow the dissection of many different tissue types into single cells, however, a wide variety of fluid-jet settings are available for dissecting different types of tissues.
The high pressure saline jet of a fluid-jet catheter may be of a single coherent stream, or may be of many geometric styles. Regardless of the pattern, the high velocity saline jet produces an immediate region of reduced pressure. Tissue is drawn into the path of the saline jet, and dissected free in the form of cell clusters. The cell clusters are then retrieved outside the flexible endoscope. The size of the fluid-jet orifice may also influence the effectiveness of the retrieval tube. The delivered cell clusters may then be re-suspended in a liquid based cytopreservative and prepared for analytical cytology.
Liquid-based analytical cytology is better than using fixed specimens because liquid-based cytology allows for conventional cyto-analysis of the cell clusters, thus allowing advanced adjunctive screening, such as flow cytometry and immunochemistry. Cell clusters may be examined with monoclonal or polyclonal antibodies to detect viral antigens of CMV, HSV and varicella zoster virus. In situ DNA or RNA hybridization using the polymerase chain reaction could also be used to detect the presence of viral DNA or RNA. These tests are rarely used in conventional sampling techniques because of the difficulty in obtaining an adequate sample. Once a sample is fixed in formalin, as are most endoscopic samples, analysis is limited. Current trends of endoscopic diagnosis seem primitive when compared to the tremendous data potentially gleaned from liquid-based cell suspensions.
Flexible endoscopes usually have at least one lumen employed for the management of endoscopic pathology. The fluid-jet catheter of the present invention uses the same lumen as do other techniques. Likewise, to sample an area of interest, the end piece of the fluid-jet catheter is positioned the same way as other techniques. With a foot switch, a high velocity saline jet is activated, and the corresponding cell clusters are delivered to a cell trap. The cell trap is removed, and the sample is re-suspended in a cytopreservative. The cell trap is replaced, but the fluid-jet catheter need not be removed from the endoscope port, unlike current techniques. The system is then ready for another session. The entire process should take less than ten seconds, a savings of over one minute per biopsy. This means the patient is under anesthesia up to fifteen-minutes less for ten biopsies taken during a procedure.
In addition to shorter biopsy times, there are several other therapeutic benefits to using fluid-jet catheters. Since a fluid-jet catheter could decrease the amount of time to remove diseased tissue, it may foster new initiatives in less invasive treatments. Conditions such as Polyposis coli, obstructive esophageal tumors, herniated disks, and gynecological tumors may take less time to treat using the fluid-jet endoscope catheter.
The dissected tissue may be captured in bridal crinoline, a 100% nylon fabric that is compatible with liquid-based cytology. The filtered cell clusters are then washed and re-suspended in a cytopreservative. Thin layer cytology slides are prepared using either an automated cell preparation station or a cyto-centrifuge, and are stained with Hematoxylin and Eosin. The slides may be visually inspected under a microscope.
A preferred embodiment of the fluid-jet catheter of the present invention is preferably at least five feet long, and less than 3.0 mm in outside diameter. The methods used to deliver the dissected tissue from the tip of the fluid-jet to the proximal end of the catheter involve either a positive pressure principle from the fluid-jet, or a negative pressure principle from wall suction. The fluid-jet is capable of exerting up to 20,000 psi. Ideally, the positive pressure generated from the high pressure fluid-jet will be such that the cell clusters are effectively pushed into and out of the retrieval tube.
Cytopreservatives are used to enhance the long term stability of cells dissected from tissue by fluid-jet. For example, hog intestinal mucosa remain well preserved in Cytorich red(copyright), a slightly hemolytic cytopreservative, for several hours. Eventual, practical, widespread use of a fluid-jet endoscopic catheter will require the cell suspension to be stable for cytoanalysis for at least one week. Several commercially available cytopreservatives may be used and compared in their efficacy of preservation for up to one month. Fluid-jet dissection of tissue may have no untoward effects upon the cell suspension, or perhaps one cytopreservative is more effective than others.
These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings.